I think the idea of (F2P )minigames is very interesting to bring new players to EXODE. If they like it, they will see what else you can do in EXODE. That being said, i think there will have to be enough content (in the main game )to keep them entertained or they might lose interest very quickly.

I like the 'space soccer' idea a lot to, in my head it has a 'blood bowl' vibe, smashing and brawling your way to the goal. While the other team might be very agile or fast depending on your faction.

Another idea for a minigame could be; you control the alien ships and have to make sure nobody escapes from a space station. Playing this game should also teach you how to evacuate more succesfully.